144 0001783984 XXXXXXXX LIVE 0001561550 Datadog, Inc. 001-39051 620 8th Avenue, 45th Floor New York NY 10018 8663294466 ALEXIS T. LE-QUOC Director Officer Class A Morgan Stanley Smith Barney LLC Executive Financial Services

1 New York Plaza 8th Floor New York NY 10004

41468 5905043.20 323270704 10/01/2025 NASDAQ Common 10/01/2025 Exercise of Stock Options Issuer N 41468 10/01/2025 Cash N 10b5-1 Sales for ALEXIS T LEQUOC

620 8th Avenue, 45th Floor New York NY 10018

Class A 09/02/2025 41468 5549532.55 ALEXIS T LEQUOC

620 8th Avenue, 45th Floor New York NY 10018

Class A 09/02/2025 13884 1858328.97 10b5-1 Sales for ALEXIS T LEQUOC

620 8th Avenue, 45th Floor New York NY 10018

Class A 08/05/2025 41468 5576002.91 10b5-1 Sales for ALEXIS T LEQUOC

620 8th Avenue, 45th Floor New York NY 10018

Class A 07/14/2025 41468 5775376.62 Securities to be sold, acquired through RSU/PSU or upon option exercise, were registered on Form S-8. 10/01/2025 09/05/2023 /s/ Alexis T. Le-Quoc